In irrigation systems the water used for irrigation purposes frequently carries with it foreign matter such as grains of sand, small pieces of wood, parts of plants, algae and the like. This material is apt to stop and block the delicate mechanism of some of the used sprinkler devices or part of other irrigation systems.
The likelihood of blocking of flow is even more serious in drip irrigation systems where the blocking of one outlet might interfere with the proper function of the whole system.
It is therefore customary to pass the irrigation water through filters before it reaches the respective water dispensing means, be these sprinklers or other outlet ports of drip or other irrigation devices.
The filtering devices obviously accumulate, during the period of use, considerable quantities of matter and above all the screening means of the filter become clogged so that the filter becomes useless. It has been suggested therefore to provide certain screening filters which perform the cleaning operation mostly by mechanical means, such as brushes combined with periodical flushing.
Such arrangements are rather complicated, they are not sufficiently reliable and increase the cost of the irrigation system considerably.